Antenna



2 Sheets-Sheet l R. (Z. RAYMOND ANTENNA g A mm mm March 21, 1951) FiledDec.

. INVENTOR. RICHARD c. RAYMOND ATTORNEY March 21, 195G R. c. RAYMOND2,5]l,94

ANTENNA Filed Pee. 10, 1945 2 Sheets-Sheet 2 III/III I III/II I0 (9 I \om 9 u. I:

I r INVENTOR. RICHARD c. RAYMOND EAL-4L9 ATTORNEY Patented Mar. 21, 1950STATES PATENT OFFICE ANTENNA Application December 10, 1945, Serial No.634,099

UNITED 6 Claims.

This invention relates to radio transmitting and receiving antennas.More particularly it relates to antennas adapted to radiate or receivecircularly polarized electrical energy.

2 nection with .the accompanying drawings in which:

Fig. 1 is a diagrammatic sketch showing the equivalent electricalcircuit employed in antennas The attempts of the prior art to radiate orre- 5 constructed in accordance with the principles of ceive circularlypolarized energy have failed for this invention; several reasons. Amongthe most important Fig. 2 is a cross-sectional view of an antennareasons for this failure was the general failure structure embodying theprinciples of this invento radiate the energy from radiators havin ation which radiates circularly polarized energy 1rigidly controlled andexact phase difierence in parallel to the axis of the akriitenntastruczure he currents flowing in them. The more general Fig. is anend'view of -e an enna 5 rue ure failure has been made due to theinability to feed of Fig. 2 shoWing the location of the radiators; asingle coaxial line with energy from a source Fig. 4 is across-sectional View of an antenna of single phase power and then toconvert this structure embodying the principles of the presphase powerto three single phase power and to ent invention which radiatescircularly polarized transfer the three phase power to the radiators.energy perpendicular to the axis of the antenna It is an object of thepresent invention to prostructure; and vide an antenna which, whenoperating as a Fig. 5 is an end view of the antenna structuretransmitting antenna, is fed from a single source of Fig. 4 showing theradiators. and radiates circularly polari energy parallel For simplicityof description the case of a transto its structure and, when operatingas a receiving mitting antenna isdiscussed in this specification a n a,receives circularly l i d energy p but it is to be understood that theelectrical and allel to its structure and delivers it through a otherprinciples apply with equal force t single transmission line to areceiver. eiving t It is also an object of the present invention toReferring more particularly 1-, Fig 1 the provide an antenna which, whenOperating as a cult employed in the antennas of this inventiontransmittin antenna, is fed from a single source for converting Singlephase energy into three and radiates circularly polarized energyperpenphase energy and Vice Versa is generally dlcular to its structureand, when operating as a I ignated by m single phase energy is f d intoreceiving antenna, rece ves circularly polarized the terminals H, Fromterminals H H the energy perpendicular to its structure and deli energyis divided into three distinct paths or cirit through a singletransmission line toa receiver. Quits denoted by '2, l3, and m which arecom It Is ,anmher Qblect of the P n mventlon nected to radiators l5, l6,and I1 respectively. to pr0v 1de devlce for Converting smgte pha,seResistor I8 is connected between circuits [2 and Into three phase energyWhose adlustabll' I3, capacitance I9 is in circuit [3, and inductanceity insures 120 degree phase difference of the 201s in circuit I 4 threephase currents.

It is a further object of the present invention It Is ob-vlous from thefimdamental fuinctlons of the resistance I8, capacitance l9, andinductto provide a transmission line for feeding energy 20 th t th t 1between receiving or transmitting apparatus and 40 ance a e curren re at cnfcu} antennas which are associated in the radiation m are i theCurrent m P m of circularly polarized energy and in which there phasewith m h Current m clrcult is a variable relative phase difference ofthe three ieads the f 'f 12 by a phase currents he current in circuit [4lags the current in cir- Generally this invention comprises a coaxial 5Cult W 120 degrees ttire: airs;tttzaarrirait cti 1 havin a constant .imedance ever n fisher? along is length. Two COidllCtOlSOf a i axiallinegltis fedfrom a s z pha'se d io of justable impedance are attachedto the inner energywere Section is J0me 0 conductor of the taperedsection of the coaxial axial line 3| at 33 and t0 the antenna pp line atits larger end and feed energy to two of Structure 30 at The taper ofsection 32 the radiators. The outer conductor of the coaxial andrelative diamgters 0f the g t d ollllfi line is connected to a thirdradiator. The cur- Conduc in that Sec 10 e c be its 0 arrents in each ofthese radiators is 120 degrees acteristic mpeda ce re a ns unchan ed outof phase t t current in ith of th throughout its entire length. Innerconductor others. 3'6 of tapered secticin 32 is joined to conductors .31

Other objectsfeatures, and advantages of this and 38 con e ed 0radiators 39 d specinvention will suggest themselves to those skilledtively. Outer conductor .34 of this tap d secin the art and will becomeapparent from the foltion is connected to outer wall 4| of housing 30lowing description of the invention taken in conwhich acts as acontinuation of the outer conductor beyond tapered section 32 and isconnected to radiator 42.

Conductors 3i and 38 are secured to conductor 36 by any suitable meanssuch as screw joints 43 and 44. At their other ends conductors 31 and 38are provided with internally threaded portions 45 and 46 respectivelyinto which screws 41 and 48 fit. Plungers 49 and 50 are attached toscrews 41 and 48 respectively and are held in place against any lateraldisplacement by fingers BI and 52 or by any other suitable means.

Plungers l9 and 50 fit respectively into longitudinal openings 53 and 54in conductors 3! and 38. They extend into these openings substantiallyone quarter wavelength corresponding to the central frequency of theoperating range.

Plunger ll} is in contact with the inner circumference of section 53thereby producing a shorted one quarter wavelength section which, as iswell known, possesses inductive characteristics. This is the inductance29 of the equivalent circuit shown in Fig. l. Plunger 50 is not incontact with the inner circumference of section 54, therefore it followsthat section 54 is an open circuited one quarter wavelength line andpossesses capacitive characteristics. This is the capacitance it! of theequivalent circuit shown in Fig. l.

Screws 4'! and 48 may be manually positioned in threaded sections 45 and46 to move plungers 49 and 50 thereby adjusting the effective electricallength of sections 53 and 54. To change the optimum operating frequencythese plungers are moved so that sections 53 and t remain one quarterwavelength, as shown, so that the currents in conductors 31 and 38 are120 degrees out of phase with each other, Changes in the relativepositions of plungers 49 and 59 will change this phase relationship.Conductors 3! and 38 are permanently secured within housing in theposition shown by the cylindrical dielectric supports 55 and 56.

A folded section 5'! is attached outside of housing 30 to outerconductor 4 I In this embodiment it is electrically connected at its endremote from the radiators and, therefore, acts as a choke to preventconductor 4i itself from acting as a radiator.

The radiators 39, 10, and 42 are physically positioned 120 degrees apartat the end of housing 30 and perpendicular to its longitudinal axis andradiate energy in a forward direction parallel to the axis of thehousing 30.

When it is desired to radiate energy in a direction perpendicular to theaxis of housing 30, the same structure may be used with the modificationof a few details which may be understood by referring to Figs. 4 and 5.Coaxial line 3|, tapered section 32, and conductors 37 and 38 and theirassociated parts such as plungers 49 and 50 are similar to thecorresponding parts in the embodiment just described. In thisembodiment, however, outer conductor 6i of housing 30, instead of beingconnected directly to one of the radiators as in the previouslydescribed embodiment, is terminated along a plane perpendicular to thelongitudinal axes of conductors 3i and 38 a distance away from radiators62 and 63 which are connected solely to conductors 3'! and 38respectively. These radiators instead of being perpendicular to thelongitudinal axis of their respective conductor make an angle of 30degrees with it. A cylindrical element 64 is, in this embodiment,electrically connected to the radiator end of conductor 6! and foldedback parallel to that conductor so that it serves asthe third radiator.The radiated energy from radiators 62, 63 and 64 combine to producecircularly polarized radiation which is perpendicular to the axis ofhousing 3|].

It is seen from the above description of the present invention that theantennas described have wide application and usefulness and thatconsiderable utility may be added to apparatus by associating with iteither or both embodiments described.

While there has been here described what is at present considered to bethe preferred embodiment of the invention, it will be obvious to thoseskilled in the art that various changes and modifications may be madetherein without departing from the scope of the invention.

What is claimed is:

1. In an antenna system for propagating perpendicular to said antennastructure circularly polarized waves, a coaxial transmission line, threeradiating elements, the first of said radiating elements being a foldedone-quarter wavelength section of the outer conductor of saidtransmission line, the second of said radiating elements being connectedto the inner conductor of said transmission line through a capacitance,and the third of said radiating elements being connected to the innerconductor of said transmission line through an inductance, and means foradjusting said capacitance and inductance whereby the phase relationshipbetween the currents in said radiating elements may be adjusted.

2. In an antenna system for propagating perpendicular to said antennastructure circularly polarized waves, a coaxial transmission line, threeradiating elements, the first of said radiating elements being a foldedone-quarter wavelength section of the outer conductor of saidtransmission line, the second of said radiating elements being connectedto the inner conductor of said transmission line through a capacitance,and the third of said radiating elements being connected to the innerconductor of said transmission line through an inductance, and means foradjusting said capacitance and inductance whereby the optimum frequencyof said system may be altered.

3. In an antenna system for propagating perpendicular to said antennastructure circularly polarized waves, a coaxial transmission line, threeradiating elements, the first of said radiating elements being a foldedone-quarter wavelength section of the outer conductor of saidtransmission line, the second of said radiating elements being connectedto the inner conductor of said transmission line through a capacitance,and the third of said radiating elements being connected to the innerconductor of said transmission line through an inductance, the values ofsaid inductance and said capacitance being such that the currents insaid radiating elements are separated from each other by degrees.

4. An antenna for radiating circularly .polarized waves comprising atapered coaxial transmission line, means for connecting the smaller endof said transmission line to a source of electromagnetic energy, first,second and third energy radiating elements having coplanar axes, aconductive sleeve for connecting said first radiating element to thelarger end of the outer conductor of said coaxial line, first and secondparallel conductors disposed within said sleeve for connecting saidsecond and third radiating elements to diametrically opposite points onthe larger end of the inner conductor of said coaxial line, said firstand second conductors-comprising variable impedance means for varyingthe phase of energy supplied to said second and third radiatingelements.

5. An antenna for radiating circularly polarized waves comprising atapered coaxial transmission line, means for connecting the smaller endof said transmission line to a source of electromagnetic energy, first,second and third radiating elements having coplanar axes, said elementsbeing so arranged that the axes of said three elements meet at a commonpoint, a conductive sleeve for connecting said first radiating elementto the larger end of the outer conductor of said coaxial line, first andsecond parallel conductors disposed within said sleev and parallel tothe axis thereof for connecting said second and third radiating elementsto diametrically opposite points on the larger end of the innerconductor of said coaxial line, said first and second conductors eachcomprising first and second conductive elements, variable capacitivemeans j0ining said first and second conductive elements of said firstconductor, and variable inductive means joining said first and secondconductive elements of said first conductor.

6. An antenna for radiating circularly polarized waves comprising atapered coaxial transmission line, means for connecting the smaller endof said transmission line to a source of electromagnetic energy, first,second, and third radiating elements having coplanar axes arranged sothat the axes of said three elements meet at a common point at angles ofsubstantially 120 degrees, a conductive sleeve for connecting said firstradiating element to the larger end of the outer conductor of saidcoaxial line, first and second parallel conductors disposed within saidsleeve and parallel to the axis thereof for connecting said second andthird radiating elements to diametrically opposite points on the largerend of the inner conductor of said coaxial line, said first and secondconductors each comprising first and second colinear conductiveelements, variable capacitive means joining said first and secondconductive elements of said first conductor, said capacitive means beingdisposed in a coaxial relationship to said first and second conductiveelements, and variable inductive means joining said first and secondconductive elements of said second conductor, said inductive means beingdisposed in a coaxial relationship to said first and second conductiveelements.

RICHARD C. RAYMOND.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,014,732 Hansell Sept. 17, 19352,239,724 Lindenblad Apr. 29, 1941 2,245,693 Lindenblad June 17, 19412,286,179 Lindenblad June 9, 1942 2,297,516 Walter Sept. 29, 19422,368,286 Carlson Jan. 30, 1945 2,420,967 Moore May 20, 1947

